Aware, Inc.

Broadcom Corporation

Christopher C Cunningham

Jianming Zhu

Murat Belge

Igor Tkachov

To assist with the detection of unfiltered device(s), a system observes how the received noise changes between two links as the transmit signal is changed. Harmful unfiltered nonlinear devices will generate significant noise that depends on the transmitted signals; therefore, this additional noise can be quantified to some extent by comparing the observed noise for two different transmit signals. The total noise can be determined from the SNR if the received signal is known. The received signal may be read directly in some non-standard systems, or it may be determined from the known transmit signal and channel attenuation, which is sometimes the case in standard-compliant links, but often with a relatively large error. To circumvent this problem, certain embodiments of this invention only consider the change in noise between two links with the same channel attenuation. This differential comparison makes it unnecessary to accurately know the channel attenuation.

Method and system for detecting non-linear devices

A system and method for controlling a performance of a communication link in a data communication system comprises mapping performance of a communication link, as characterized by metrics computed at a first protocol layer in a network device, to quality of the communication link as characterized by metrics computed at a second protocol layer in the network device. The second protocol layer is higher than the first protocol layer in a protocol stack running on the network device. A setting of one or more communication link controls at the first protocol layer is adjusted to attain a given communication link performance at the first protocol layer that, according to the mapping between the communication link performance at the first protocol layer and the quality of the communication link at the second protocol layer, corresponds to a target quality of the communication link at a second protocol layer.

Adjusting controls at the physical layer to control link quality at higher layers

One exemplary aspect is to detect the presence of one or more types of faults affecting DSL communications. Upon their detection, a message can be generated that recommends corrective action. Furthermore, another exemplary aspect is to estimate the rate impact of the detected fault in some cases. One exemplary aspect of certain embodiments is to detect the presence of one or more faults that affect DSL communications, and upon their detection, generating, for example, a message that recommends corrective action. In this context, a fault can be one or more metallic faults, malfunctioning modems, or something else that affects the measured attenuation but is not normally attributable to normal DSL transmission lines.

Methods and systems for detecting metallic faults affecting communications links

A modem or associated computing or testing device is configured to detect the presence of one or more faults that affect DSL communications, and upon their detection, generate, for example, an indication, communication or message that recommends corrective action. In this context, a fault is generally caused by one or more unfiltered devices, impulsive noises, malfunctioning modems, or other factor that does not affect measured attenuation or measured noise, but does affect the signal-to-noise ratio (SNR) of the link. In addition to being able to generate a message guiding a user through corrective action, the system can estimate the rate impact of the detected fault.

Detecting faults affecting communications links

A three-port TDR front end comprises numerous components. An exemplary three-port TDR front end is a DSL modem. Information-bearing TDR signals are distorted as they pass through these components. With a perfect model of the response of its front-end, a TDR system usually can compensate for the effects of its front-end. In reality, however, the electrical characteristics of each component vary from design-to-design, board-to-board, and slowly over time The result is imperfect knowledge about the true response of the front-end, errors in the model of the front-end, and degraded TDR performance. At least for this reason it is important to precisely calibrate the response of the TDR front-end through the use of a TDR modeling system.

Modeling and calibrating a three-port time-domain reflectometry system

Data is collected and interpreted in response to one or more transmitted signals to determine if an interfering device is present. If an interfering device is present, a message is generated and presented to a user indicating, for example, that the installation of a micro-filter is appropriate. The system can then determine if the micro-filter was installed properly and, for example, commence communication or, if the micro-filter(s) did not solve the problem, initiate communication with or contact a technician.

Nonlinear device detection

A three-port TDR front end includes numerous components. An exemplary three-port TDR front-end is a DSL modem. Information-bearing TDR signals are distorted as they pass through these components. With a perfect model of the response of its front-end, a TDR system usually can compensate for the effects of its front-end. In reality, however, electrical characteristics of each component vary slowly over time. The result is imperfect knowledge about the true response of the front-end, errors in the model of the front-end, and degraded TDR performance. It is important to calibrate the response of the TDR front-end through using a TDR modeling system that determines at least three respective responses when the third port is connected to each of at least three different devices, determining three parameters that characterize a front-end, and using the three parameters to predict the system response when the front-end is connected to any device.

A three-port TDR front end comprises numerous components. An exemplary three-port TDR front end is a DSL modem. Information-bearing TDR signals are distorted as they pass through these components. With a perfect model of the response of its front-end, a TDR system usually can compensate for the effects of its front-end. In reality, however, the electrical characteristics of each component vary from design-to-design, board-to-board, and slowly over time. The result is imperfect knowledge about the true response of the front-end, errors in the model of the front-end, and degraded TDR performance. At least for this reason it is important to precisely calibrate the response of the TDR front-end through the use of a TDR modeling system.

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Brighton, MA, United States of America

Christopher C Cunningham